[NumLock]

Код:

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Grids;

type
  TForm1 = class(TForm)
    StringGrid1: TStringGrid;
    procedure StringGrid1GetEditMask(Sender: TObject; ACol, ARow: Integer;
      var Value: String);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.StringGrid1GetEditMask(Sender: TObject; ACol,
  ARow: Integer; var Value: String);
begin
  if ACol<=2 then Value:='99999999;0; ' else Value:='LLLLLLLL;0; ';
end;

end.